But we're going to see alot of power-assist bikes on the roads. A 1-horsepower 2-cycle engine weighs 6 pounds and mounted on a bicycle will give me 400 mpg fuel economy @ 14 mph, top speed 20 mph. One tank of gas will take me 50 miles. Costs $600 for a unit that mounts on a bicycle. That'll get me to work in under an hour. I could just peddle home because it's mostly downhill, so I'd only pay for 1-pint of gas per week to top-up the tank. Now if it's raining or snowing, that's another problem. Some companies sell windfairings, but they're expensive. Bike plus engine overall cost about $1000, gas is extra.... about the same cost for a year of subsidized public transit.

It doesn't get much better (or worse) than that in terms of economic commuting. Gas would have to be 20-times more expensive ($1000 per barrel of oil) before power-assist cyclists would start complaining. Freight vehicles will become uneconomical long before them. I'm not saying it won't happen, but it might not happen in the next couple decades. To get better fuel economy would require something impractical I think.